An extremely large percentage of the world's vehicles run on gasoline using an internal combustion engine. The use of such vehicles, more specifically the use of vehicles which rely on fossil fuels, e.g., gasoline, creates two problems. First, due to the finite size and limited regional availability of such fuels, major price fluctuations and a generally upward pricing trend in the cost of gasoline are common, both of which can have a dramatic impact at the consumer level. Second, fossil fuel combustion is one of the primary sources of carbon dioxide, a greenhouse gas, and thus one of the leading contributors to global warming. Accordingly, considerable effort has been spent on finding alternative drive systems for use in both personal and commercial vehicles.
Electric vehicles offer one of the most promising alternatives to vehicles that use internal combustion drive trains. To be successful, however, an electric vehicle must meet the consumers' expectations relative to performance, range, reliability, lifetime and cost. These expectations, in turn, place considerable importance on the design and configuration of the electric vehicle's rechargeable batteries since the batteries are currently one of the most expensive components associated with an electric drive train as well as one of the primary limitations to vehicle range. Furthermore, limited battery lifetime has a direct impact on long-term vehicle reliability, a problem that is clearly exacerbated by high battery replacement costs.
Accordingly, what is needed in the art is a means of extending the lifetime of a battery pack without incurring excessive additional costs. The present invention provides such a means.